1. Field of the Invention
The present invention relates to a multiple wet clutch device and, more particularly, it relates to a multiple wet clutch device which can advantageously be used with an apparatus in which a drive shaft is driven through a pulley.
2. Description of Related Art
Generally speaking there are two types of clutch devices: wet type and dry type. The dry type of clutch is relatively small but has a number of drawbacks. The drawbacks include reduced (relative to wet type clutches) durability of the frictional portion of the clutch, tendency to produce large (relative to wet type clutches) noises and proclivity toward shock occurrence when the clutch is engaged. Further, in the dry type of clutch, foreign matter tends to penetrate into the areas between the clutch plates.
On the other hand, wet type clutches, that is, those types of clutches in which the clutch plates are disposed in oil, do not suffer the above-mentioned drawbacks to the same extent as the dry type clutches. More specifically, the frictional portion of a wet type clutch has high durability. Further, wet type clutches can be engaged and disengaged without causing much noise. However, because of their peculiar construction, it is difficult to make wet type clutches small. Wet type clutches have a large axial dimension. There are other problems. For example, during operation of a wet type clutch, it is difficult to cool the oil in which the clutch plates are immersed and it is also difficult to cool the coil which electromagnetically actuates the clutch. Accordingly, a need has arisen for a special cooling apparatus.